Initially concepts for activities, then once concept approval is gained, detailed system design for prototyping by the code team.
Once prototypes are up and running, several iterations of testing & feedback until the prototype is either approved for inclusion in the game or scrapped.
I'm generally working on several prototypes at a time.
I'd be more specific, but NDA n all that ...
My portfolio is a bit out of date and unfinished really, I guess it gives the impression that I am only a level designer, which is not the case.
I should put some more work into it, but I am happy with my job right now and busy playing an MMO in my spare time so ...